Air cooled internal combustion engine



June 20, 1961 R. KLOSS 2,989,042

AIR COOLED INTERNAL COMBUSTION ENGINE Filed Sept. 16, 1959 INVENTOR AIR 'COOLED INTERNAL COMBUSTION ENGINE Richard Kloss, Koln-Buchforst, Germany, assignor t Klockner-Humboldt-Deutz Aktiengesellschaft, Koln,

Germany Filed Sept. 16, 1959, Ser. No. 840,344 Claims priority, application Germany Sept. 25, 1958 3 Claims. (Cl. 12341.65)

The present invention relates to internal combustion engines and, more particularly, to air cooled internal combustion engines in which the weight rate of cooling air is controlled by thermostatically controlled means adapted to throttle the flowing oif cooling air in conformity with the temperature of said cooling air.

With internal combustion engines of the above mentioned type, it was heretofore necessary to prevent the throttle from completely closing at any time in order to make sure that the thermostat will still be acted upon by cooling air even at conditions of operations when normally the weight rate of cooling air should have been reduced to zero in order to prevent an over-cooling of the engine. This necessity to hold the throttle open below the socalled switch point is disadvantageous inasmuch as even the smallest weight rate of cooling air still represents a multiple of that quantity of cooling air which will sufi'ice for maintaining the responsiveness of the thermostat. The relatively high weight rate of cooling air brings about unnecessarily long heating-up periods when starting the engine and also brings about over-cooling of the engine if it is temporarily relieved as for instance when driving downhill over a longer distance.

It is, therefore, an object of the present invention to provide an arrangement which will overcome the above mentioned drawbacks.

It is another object of this invention to provide an air cooled internal combustion engine with thermostatically controlled means for controlling the rate of cooling air, which will allow a complete closure of said thermostatically controlled means for controlling the cooling air when conditions call for such closure.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawing, in which:

FIG. 1 diagrammatically illustrates, partly in section, an air cooled internal combustion engine with a control arrangement according to the present invention.

FIG. 2 shows a slight modification of the control arrangement of the invention.

The control arrangement of the present invention for controlling the cooling air employed for cooling the engine is characterized primarily in that the thermostat responsive to the temperature of the cooling air is controlled in a by-pass passage by-passing the throttle controlling the major portion of the off-flowing cooling air. According to this arrangement, the throttle is adapted below the so-called switch point to close completely. In such instance, merely the quantity of cooling air acting upon the thermostat is permitted to flow through, which quantity is to be held as low as possible. This limitation of the weight rate of cooling air is of considerable importance.

Patented June 20, 1961 "ice While the by-pass channel may be arranged and designed in any convenient manner, it is also possible to provide the bypass passage of the invention in the control or throttle means themselves.

Referring now to the drawing in detail, the arrangement shown in FIG. 1 represents a portion of a one-cylinder internal combustion engine 1 with an air cooled cylinder 2 equipped with transverse cooling fins 2a. As will be clear from the drawing, fresh air is passed by an axial blower 3 between the fins 2a while cowling means 4 and 5 are provided for respectively guiding the cooling air to and away from the cylinder 2 to be cooled.

For purposes of controlling the weight rate of cooling air passing around the cylinder 2 through the cowling means 4 and 5, a throttle 6 is provided for more or less throttling the heated-up and flowing-off cooling air. The said throttle 6 is controlled by a thermostat 7 in conformity with the temperature of the cooling air passed through the cooling zone of cylinder 2, said thermostat being operatively connected to throttle 6 by link means 9. The thermostat 7 is arranged in a by-pass passage 8 by-passing throttle 6. When throttle 6 occupies its closed position shown in the drawing, merely the relatively small quantity of air required for keeping the thermostat 7 working passes through the cooling zones of cylinder 2 and the by-pass passage 8. The arrangement of FIG. 2 differs from that of FIG. 1 merely in that the by-pass passage 10 is arranged in the throttle itself.

It is, of course, to be understood that the present invention is, by no means, limited to the particular constructions shown in the drawing but also comprises any modifications within the scope of the appended claims.

What I claim is:

1. In an internal combustion engine having an air cooled cylinder: cooling air delivery means for delivering cooling air to and around the cylinder to be cooled, conduit means arranged adjacent said cylinder and having a discharge opening for conducting cooling air heated up by said cylinder away from the latter, adjustable throttling means arranged in said conduit means and movable from a closing position into an open position and vice versa for controlling the escape of cooling air heated up by said cylinder through said discharge opening, by-pass means communicating with said conduit means and bypassing said discharge opening When said throttling means is in its closing position for continuously discharging at least a portion of the air heated up by said cylinder to be cooled, thermostatic means arranged in the path of the cooling air from said cylinder through said by-pass means, and means operatively connecting said thermostatic means to said throttling means for actuating the latter.

2. In an internal combustion engine having an air cooled cylinder: cooling air delivery means for delivering cooling air to and around the cylinder to be cooled, conduit means arranged adjacent said cylinder and having a discharge opening for conducting cooling air heated up by said cylinder away from the latter, adjustable throttling means arranged in said conduit means and movable from a closing position into an open position and vice versa for controlling the escape of cooling air through said discharge opening, by-pass means arranged within said conduit means and by-passing said discharge opening when said throttling means is in its closing position, said by-pass means having an inner cross section considerably less than that of said discharge opening, thermostatic means arranged in the path of the cooling air from said cylinder through said by-pass means, and link means operatively connecting said thermostatic means with said throttling means for actuating the latter.

3. In an internal combustion engine having an air cooled cylinder: cooling air delivery means for delivering cooling air to and around the cylinder to be cooled, conduit means arranged adjacent said cylinder and having a discharge opening for conducting cooling air heated up by said cylinder away from the latter, adjustable throttling means arranged in said conduit means and movable from a closing position into an open position and vice versa for controlling the escape of cooling air through said discharge opening, by-pass means arranged Within said throttling means and by-passing said discharge opening when said throttling means is in its closing position, thermostatic means arranged in said by-pass means, and link means operatively connecting said thermostatic means with said throttling means for actuating the latter.

References Cited in the file of this patent UNITED STATES PATENTS 2,664,862 Walker Jan. 5, 1954 2,827,026 Mall et al. Mar. 18, 1958 2,861,554 Stump Nov. 25, 1958 FOREIGN PATENTS 1,005,564 Germany May 2, 1957 

